A Link Between Investment Biases and Cortisol and Testosterone Levels
Financial markets are full of pricing anomalies, and their existence is often explained by human behavior. Behavioral finance postulates that cognitive irrationality is manifested in biases like the disposition effect (the tendency of people to sell assets that have increased in value, but keeping assets that have dropped in value in portfolio) or overconfidence bias (the tendency of people to be more confident in their own abilities). There are some papers which directly link investment decision making caused by these biases to actual physiology of investors (for example, a known impact of testosterone on investment performance). A new research paper written by Nofsinger, Patterson, and Shank examines not only testosterone but also cortisol levels of testing subjects and then compares their performance in a mock investment contest. Both hormones are strongly related to higher portfolio turnover and inability to accept losses, with cortisol levels even more significant than testosterone.